How to read/write from erlang to a named pipe ?
- by cstar
I need my erlang application to read and write through a named pipe.
Opening the named pipe as a file will fail with eisdir.
I wrote the following module, but it is fragile and feels wrong in many ways. Also it fails on reading after a while. Is there a way to make it more ... elegant ?
-module(port_forwarder).
-export([start/2, forwarder/2]).
-include("logger.hrl").
start(From, To)->
spawn(fun() -> forwarder(From, To) end).
forwarder(FromFile, ToFile) ->
To = open_port({spawn,"/bin/cat > " ++ ToFifo},
[binary, out, eof,{packet, 4}]),
From = open_port({spawn,"/bin/cat " ++ FromFifo},
[binary, in, eof, {packet, 4}]),
forwarder(From, To, nil).
forwarder(From, To, Pid) ->
receive
{Manager, {command, Bin}} ->
?ERROR("Sending : ~p", [Bin]),
To ! {self(), {command, Bin}},
forwarder(From, To, Manager);
{From ,{data,Data}} ->
Pid ! {self(), {data, Data}},
forwarder(From, To, Pid);
E ->
?ERROR("Quitting, first message not understood : ~p", [E])
end.
As you may have noticed, it's mimicking the port format in what it accepts or returns.
I want it to replace a C code that will be reading the other ends of the pipes and being launched from the debugger.
